....That's correct for a routine conversion, but the OP wants to convert an RMD, which is not allowed.....

If the OP has some earned income and is eligible for any deductable retirements accounts(IRA, 401K, etc) then the RMD can be deposited into one of those to get an offsetting deduction so the net tax effect will be essentially zero.

If they are over 70 and not working that does not help much, but people who are younger and still working can often do this with RMD's from inherited IRA's